Study on polarization spectrum and annealing properties of 45° tilted fiber grat

We have investigated the whole polarization-extinction-ratio (PER) spectrum and annealing properties of 45°-tilted fiber gratings (45°-TFGs). Experimental results show the PER spectrum of 45°-TFGs is a Gaussian-like profile and covers a 540?nm bandwidth from 1260 to 1800?nm, in which the bandwidth w